U.S. Pat. Nos. 3,269,141 and 3,520,148 describe unitary self-cooling containers for potable materials which operate with carbon dioxide cartridges in conjunction with heat exchange means such as a coil or a jacket into which the refrigerant gas flows.
In U.S. Pat. No. 3,269,141 a compressed gas is released to flow without restriction through a coil immersed in the beverage, utilizing the cooling which occurs due to gas expansion. In U.S. Pat. No. 3,520,148 a cartridge of compressed gas is released in such a manner that the released gas is directed over the outside of the can by a cardboard shield, cooling being achieved as the gas expands and flows around the container.
U.S. Pat. No. 3,636,726 describes a cooling means for beverages which utilizes chlorofluorohydrocarbon refrigerants. This self-cooling container, while reducing the temperature of the beverage to about 40.degree. F., is not entirely satisfactory. In the cooling apparatus of U.S. Pat. No. 3,636,726 gas escapes from a reservoir, passes through a throttle, and flows through a cooling coil. The beverage is cooled by this flow of expanding gas through the coil and by contact with the top surface of the reservoir, which is made of a metal of high thermal conductivity. However only one of the surfaces of the auxiliary reservoir, less than half of its total surface, is in contact with the beverage. As a consequence this beverage cooling apparatus is not sufficiently efficient for some uses. It is an object of this invention to provide an edible liquid cooling apparatus which more readily lends itself to its end uses.